1. Field of the Invention
This invention relates to automatic product checking equipment and more particularly to such equipment useful in checking the surface conditions of such a product, for example, a pill.
2. Prior Art
The use of a video envelope corresponding to a viewed object to check the acceptability of such an object or product has, in the past, utilized a fixed reference voltage, for example a standard reference cell, with which the amplitude of the envelope is compared or, alternatively, a floating reference produced by attenuating and delaying the video envelope and comparing it with the original envelope. Both of such comparison systems suffer from insensitivity to minor video envelope changes which arise when a minor, but objectionable defect, such as a scratch, appears on the surface of the product, for example a medicinal pill.
Therefore, it is a general object of this invention to overcome the disadvantages of the prior art devices, such as those set forth hereinbefore.
It is a further object of this invention to provide an improved, highly sensitive method and apparatus for checking the surface conditions of a product to determine whether that product should be accepted or rejected.